The present invention relates to a safety restraint system which includes an object or occupant classification system and more particularly to a device using fiber optics arranged in a specific pattern in a seat of a vehicle.
It is an object of the present invention to provide an occupant or object classification system and additionally one such system which can also be used to provide weight and/or position information about particular objects and/or an occupant occupying a vehicle seat. The present invention utilizes one or more fiber optic cables (which are also referred to as fibers, cables, optic fibers, optical fibers, etc.).
Fiber optic cables have been used in many applications. The typical construction of a fiber optic cable is well known and includes a light carrying center core. The center core is covered by a cladding, which acts as a mirror to reflect incident light and to keep the light within the core. The optical characteristics and more particularly the refractive indexes of the cladding and of the core will vary with application. The optical characteristics of the cable determine the transmissibility of light through the cable. A cable with a higher transmissibility provides a more efficient cable, which transmits light more effectively while a less efficient cable transmits light with greater losses. The signal measured at the output end of an optical fiber may vary relative to a signal at its input end in amplitude and/or in phase shift, etc.
In the present invention the optical characteristics of the fiber (or at least a portion thereof) change when the fiber is displaced, stressed and/or bent thereby causing a measurable change in its output.
A receiver or detector is connected to the output end of each fiber and is used to measure the output (amplitude, phase, polarization angle, etc.) of the optical fiber. This change in output is proportional to the transmissibility of the cable, which varies with displacement, stress or degree of bending of the optic fiber cable, which in turn is correlatable with the force applied to the cable. In the present invention optical cable(s) are mounted in the seat cushion or seat back of an automotive seat. As can be appreciated, a measure of the distribution of forces in the seat cushion and/or seat belt can be used to classify the object or occupant into one or more classes, as well as to identify the position of the object and/or occupant on the seat.
Accordingly the invention comprises: an object classification system comprising: a cable or plurality of such cables arranged in one or more specific patterns within a seat cushion and/or seat back, the optical characteristics of the fiber being changeable with applied force to the fiber(s). The system includes a processor responsive to the output signal from each or selective fibers for generating control signals determinative of the force(s) acting on the cables.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.